Condenser blade for air jet looms



United States Patent Karel Vystril B ae, Si s be ovak Josef Nespechal, Brno, Czechoslovakia inventors Appl. No. 760,170

Filed Sept. 17, 1968 Patented Aug. 25, 1970 Assignee Vyzkumny a vyvojovy ustav zavodu vseobecneho strojirenstvi Brno, Czechoslovakia CONDENSER BLADE FOR AIR JET LOOMS [56] References Cited UNITED STATES PATENTS 3,139,118 6/1964 Svaty et al. 139/127 Primary Examiner- Henry S. .laudon Attorney- Richard Low ABSTRACT: A guide member to be used in a condenser assembly of an air jet loom having a substantially ring-shaped configuration with inner and outer peripheral surfaces and formed with a slot extending therebetween, so that it can be separated from the weft. The inner peripheral surface of the guide member at a location opposite the slot being provided with a configuration adapted to brake the movement of air therethrough and thus balance the air stream with respect to the slot.

Patented Aug. 25, 1970 3,525,369

lake/ VyisfrZi/ J22; e7 has ae z/m/ INVENTORS CONDENSER BLADE FOR AIR .IET LOOMS BACKGROUND OF THE INVENTION The present invention relates to weaving looms.

In particular, the invention relates to air jet looms in which it is customary to employ, instead of a shuttle, a jet of air for directing the weft across the warp. With such a jet, the weft is picked through the shed by being suspended in an air stream and pulled through the shed by the movement of the jet across the warp.

In jet looms of this type, where the weft is picked through the shed by means of an air jet, there are an assembly of guide members situated one beside the other and forming an air condenser, these guide members being of a generally ring-shaped configuration and being formed with a slot extending between their inner and outer peripheries. Conventionally, the inner circumferential periphery of such blades forms part of a cone whose apex points in the direction of the movement of the weft across the warp. Thus, the apex of this cone points in the direction of the weft picking movement. The inner peripheral surfaces of the guide members serve to guide and rectify the air jet which carries the weft. The slot enables the guide member to be displaced and separated from the weft before the weft is beat-up.

In U.S. Pat. 3, 139, 118 issued on June 30, 1964 to V. Svaty et al., the general construction and arrangement of a guide member such as described is disclosed. In theory an air stream directed through the guide member of the Svaty patent if made without the slot would move at a maximum speed substantially along the center of its ring-like aperture. However, the provision of the slot, for the separation of the weft, deforms the aerodynamic nature of the moving stream by allowing some of the air to leak so that the line of maximum speed deviates from the center of the ring in the direction toward the slot, resulting in the unwanted entanglement of the weft within the slot. The Svaty patent overcomes this disadvantage by increasing the speed of the air jet through the guide member to create what appears to be a partial vacuum within the ring sucking air into the inner periphery of the guide member through the slot resulting in a movement toward the center of the ring of the line of maximum speed.

It has also been attempted to prevent the aforementioned disadvantage by covering the slots with one of the warp end sheets during the time when the weft yarn is picked through the shed. During operation, however, this solution does not perform in a satisfactory manner inasmuch as this shed position has to be accurately maintained, which requirement is very difficult to fulfill under these conditions, particularly in the case of asymmetrical weaves.

Furthermore, it is known to provide a construction wherein the slot of each guide member is of a labyrinth configuration. With such a construction continuous leakage of the air through the slot is retarded to some extent, but there nevertheless remains a component of force which has a negative effect on the weft during picking of the latter through the shed.

There are various other known attempts to solve this problem, such as by the use of suitable balls, brushes and the like in order to cover the slots, but none of these solutions is able to provide the required seal which perfectly closes the slots, so that air leakage still occurs in all of the known constructions with the result that the aerodynamics of air flow through the condenser is undesirably affected.

SUMMARY OF THE INVENTION It is accordingly a primary object of our present invention to provide a guide member construction which will avoid the above indicated drawbacks.

One object of this invention is to provide a guide member structure which will improve the picking of the weft as a result of a substantial improvement in the aerodynamics of air flow in the air condenser to assure a proper movement of the picked weft while suspended in the air stream and directed across the warp.

It is another object of the present invention to achieve these results with an exceedingly simple guide member structure.

According to the invention, the guide member has at its inner periphery, at a location opposite the slot, a configuration which brakes the movement of the air through the guide member at the location situated opposite the slot, so that in this way the jet has its part which flows at maximum speed, and in which the weft is located, spaced from the slot. This braking means takes, in accordance with the invention, the form of a part of the inner peripheral surface of the guide member which is situated opposite the slot and which has a slope different from the remainder of the inner peripheral surface of the guide member.

BRIEF DESCRIPTION OF THE DRAWING Several embodiments of the invention are illustrated in the accompanying drawing which forms part of this application and in which:

FIG. I is an elevation of one possible condenser guide member of the invention;

FIG. 2 is a section of the guide member of FIG. 1, taken in the plane of the line 22 of FIG. 1;

FIG. 3 shows an elevation of another embodiment of a condenser guide member according to the invention; and

FIG. 4 is a section similar to that of FIG. 2 but showing still another guide member structure according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The guide member of the present invention is mounted together with a series of additional guide members in a known sley (not shown), with these guide members coaxially aligned one beside the other to guide the air jet across the warp. The sley brings about the conventional reciprocating movement displacing the air condenser guide members between the operative positions which they have during picking of the weft through the shed and the displaced positions which they have during the beating up of the weft.

Each guide member includes an elongated foot or mounting portion 1 which at its upper end branches into a pair of elongated portions 2 and 3 providing the guide member with its generally ring-shaped configuration. The part 2 is curved while the part 3 is straight extending along an axis parallel to the axis of the foot 1. These branches 2 and 3 terminate in surfaces which are spaced from each other to define a slot 4 also parallel to the axis of the foot 1 by means of which the weft may be slipped out of the ring. The parts 2 and 3 of the guide member define a substantially circular opening 5 in the guide member, through which opening a jet of air is directed for picking the weft through the shed. The inner surface of the guide member is defined in part by a circumferential surface portion 6 which forms part of a cone whose apex points in the direction in which the weft is picked.

At a part of the opening 5 which is opposite and distant from the slot 4, the inner peripheral surface of the blade has a configuration which provides means for braking the movement of the air at that part of the opening 5, which is most distant from the slot 4. This braking means takes the form of an inner surface portion 7 of the guide member which has a slope different from the remainder 6 of the inner surface portion. The inner surface portion 7 in the embodimentillustrated in FIGS. 1 and 2 has a taper ratio which is larger than the circumferential surface portion 6 that forms the remainder of the inner peripheral surface of the guide member. As is clearly apparent from FIGS. 1 and 2, while the inner surface portion 7 which forms the braking means tapers in the same direction as the remainder 6 of the inner surface portion, the inner surface portion 7 is more steeply inclined and forms part of acone whose apex angle is greater than the apex of the cone of which the surface 6 forms a part.

According to the embodiment of the invention which is illustrated in FIG. 3, the braking means is formed by an inner surface portion 7 situated opposite the slot 4 and forming part of a cylinder whose axis coincides with the central axis of the opening which extends in the direction of weft movement. The inner surface portion 7 of this embodiment forms part of a cylinder whose axis is parallel to the weft picking axis, while the remainder 6 of the inner surface portion is inclined in the same way as in FIGS. 1 and 2 so that in this case also it forms part of a cone whose apex points in the direction of weft movement.

According to the embodiment of the invention which is illustrated in FIG. 4, the braking means is formed by an inner surface portion 7 situated opposite a slot 4 but inclined oppositely to the inclination of the remainder 6 of the inner surface portion which still forms part of a cone whose apex points in the direction of weft movement. With the embodiment of FIG. 4 the braking means is formed by inner surface portion 7" which forms part of a cone whose apex points in the direction opposed to the direction of weft picking.

With all of the above described embodiments of the invention the airjet which carries the weft is braked at the inner surface portions 7, 7' and 7, respectively, of the guide members so that the aerodynamic balance of the air stream is upset and deviated away from its normal course. This deviation is oppositely directed from that created by the loss of air through the slot and as a consequence reestablishes the theoretical balance of the air stream within the center of the aperture. In the case of FIGS. 1 and 2, this braking of the air movement is achieved because additional air is sucked in at the surface portion 7 as a result of the enlarged taper ratio of the surface portion 7 as compared to the surface portion 6. In the case of FIG. 3 where the surface portion 7 forms part of a cylinder, and in the case of FIG. 4 where the surface portion 7 forms part ofa cone whose apex points in the direction opposed to the direction of weft movement, the result is achieved because air leakage and turbulence both increase at the portions 7 and 7' ofthe embodiments of FIGS. 3 and 4 so that this additional air leakage and additional turbulence result also in braking of the speed of air movement at the location of the surface portions 7 and 7".

As a result of the location of the braking of the air achieved with the structure of the invention, the region of maximum speed of the air jet is shifted away from the slot 4 and placed closer to the theoretical position along the center of the aperture 5. Inasmuch as the weft which is picked moves in the part of the jet which has the maximum speed of air flow, a proper flight of the weft through the condenser is thus assured, by displacing the weft from the slot to the center of the guide member during this operation.

The structure of the invention can be used in air jet looms where a condenser made up of an assembly of these guide members is provided.

We claim:

I. The combination in an air jet loom having a plurality of .weft guide members of a generally ring-shaped configuration arranged one beside the other for guiding an air jet axially therethrough to carry said weft, said guide members having inner peripheral and outer peripheral surfaces and a slot extending therebetween to enable the guide member to be separated from said weft, the surface of said inner periphery having a portion substantially opposite said slot which is of a slope different from the remainder of the surface of said periphery, whereby movement of said air jet is radially displaced at a position between said slot and said inner peripheral portion.

2. The combination according to claim 1 wherein each of said guide members includes a foot extending outwardly from the outer periphery thereof for mounting said guide member on a rotatable sley, the foot being disposed along an axis parallel to said slot.

3. The combination of claim 1 and wherein said remainder of said inner periphery of said guide member is in the form of a surface forming part of a cone whose apex points in the direction of weft movement across the warp, the inner surface portion of said inner periphery different from said remainder, having a slope different from said remainder of said inner periphery.

4. The combination of claim 3 and wherein said inner surface portion is more steeply inclined than the remainder of said inner periphery of said guide member and forms part of a cone whose apex angle is greater than the apex angle of a cone of which the remainder of said inner periphery forms a part.

5. The combination of claim 3 and wherein said inner surface portion of said guide member opposite said slot different from the remainder, forms part of a cylinder whose axis coincides with the axis along which the weft is picked.

6. The combination of claim 3 and wherein said inner surface portion of said guide member different from the remainder is inclined at an angle forming part of a cone whose apex points in a direction opposed to the direction of movement of the air jet. 

